Precoding a transmission from a multi-panel antenna array

Abstract

The invention relates to a wireless communication device configured for use in a wireless communication system, wherein, based on one or more structural properties of a multi-panel antenna array describing how the antenna array is structured into multiple panels, a precoder is selected to be applied for a transmission from the multi-panel antenna array; and wherein an information indicative of the determined precoder is signaled to a transmit radio node; the invention further refers to a transmit radio node configured for transmitting via a multi-panel antenna array in a wireless communication system, wherein signaling indicating one or more structural properties of a multi-panel antenna array describing how the antenna array is structured into multiple panels is transmitted to the wireless communication device.

The invention claimed is: 
     
       1. A method performed by a wireless communication device configured for use in a wireless communication system, the method comprising the wireless communication device:
 determining, based on one or more structural properties of a multi-panel antenna array describing how the antenna array is structured into multiple panels, a precoder to recommend to a transmit radio node for applying to a transmission from the multi-panel antenna array; 
 signaling the determined precoder to the transmit radio node; 
 wherein the determined precoder is configured to apply, for each of the multiple panels, a panel-specific complex weight to all antenna ports corresponding to that antenna panel; and 
 wherein the panel-specific complex weight is a phase shift with unitary amplitude. 
 
     
     
       2. The method of  claim 1 , wherein the one or more structural properties include, for each of one or more spatial dimensions in which the multiple panels are arranged, a number of panels into which the antenna array is structured in that spatial dimension. 
     
     
       3. The method of  claim 1 , wherein the one or more structural properties include a spatial arrangement of the multiple panels into which the antenna array is structured. 
     
     
       4. The method of  claim 1 , further comprising receiving signaling indicating the one or more structural properties. 
     
     
       5. The method of  claim 4 , wherein the signaling is radio resource control signaling. 
     
     
       6. The method of  claim 4 , wherein the signaling is received during a procedure for configuring a channel state information process or channel state information reference signal resource. 
     
     
       7. The method of  claim 4 , wherein the signaling is physical layer signaling; wherein the signaling is included in a downlink control information message on a physical downlink control channel. 
     
     
       8. The method of  claim 4 , wherein the signaling is included in a message that conveys an uplink grant for the wireless communication device to transmit a channel state information feedback report to the transmit radio node. 
     
     
       9. The method of  claim 1 , wherein the determining comprises determining a multi-panel precoding codebook based on the one or more structural properties. 
     
     
       10. The method of  claim 9 , wherein the determining the multi-panel precoding codebook comprises determining the multi-panel precoding codebook as being one of multiple different possible precoding codebooks respectively corresponding to different possible ways in which the antenna array is structurable into multiple panels. 
     
     
       11. The method of  claim 9 , wherein the determining the multi-panel precoding codebook comprises modifying a predefined precoding codebook based on the one or more structural properties. 
     
     
       12. The method of  claim 9 , wherein the determining further comprises selecting the precoder from the determined multi-panel precoding codebook, based on measurement of one or more reference signals transmitted from the multi-panel antenna array. 
     
     
       13. The method of  claim 1 :
 wherein the precoder is determined from an inter-panel precoding codebook, wherein the inter-panel precoding codebook is a Discrete Fourier Transform (DFT) codebook; 
 further comprising signaling:
 an index indicating a recommended intra-panel precoder selected from an intra-panel precoding codebook; and/or 
 an index indicating a recommended polarization co-phasing precoder selected from a polarization co phasing precoding codebook. 
 
 
     
     
       14. The method of  claim 1 , wherein the determined precoder co-phases panels of the multi-panel antenna array. 
     
     
       15. The method of  claim 1 :
 wherein the multiple panels include at least some panels that have identical antenna port layouts and intra-panel antenna port indices; and 
 wherein the determined precoder applies the same phase offset between antenna ports that correspond to spatially adjacent panels and that have the same intra-panel antenna port indices. 
 
     
     
       16. The method of  claim 1 , wherein the determined precoder applies a phase offset between antenna ports corresponding to different panels that differs from a phase offset applied to antenna ports corresponding to the same panel. 
     
     
       17. The method of  claim 1 , wherein the determined precoder is configured to combine antenna ports corresponding to different antenna panels onto the same transmission layer. 
     
     
       18. The method of  claim 1 , wherein determining the precoder comprises determining, independently for each of the multiple panels, the panel-specific complex weight that is to be applied to all antenna ports corresponding to that panel. 
     
     
       19. The method of  claim 1 , wherein the precoder is determined based on measurement of one or more channel state information reference signals transmitted from the multi-panel antenna array on a set of one or more channel state information reference signal resources. 
     
     
       20. The method of  claim 1  wherein the one or more structural properties include a total number of the multiple panels into which the antenna array is structured. 
     
     
       21. A method implemented by a transmit radio node configured for transmitting via a multi-panel antenna array in a wireless communication system, the method comprising the transmit radio node:
 transmitting, to a wireless communication device, signaling indicating one or more structural properties of a multi-panel antenna array describing how the antenna array is structured into multiple panels; 
 receiving, responsive to transmitting the signaling and from the wireless communication device, signaling indicating a precoder that the wireless communication device recommends to the transmit radio node for applying to a transmission from the multi-panel antenna array; 
 wherein the determined precoder is configured to apply, for each of the multiple panels, a panel-specific complex weight to all antenna ports corresponding to that antenna panel; and 
 wherein the panel-specific complex weight is a phase shift with unitary amplitude. 
 
     
     
       22. The method of  claim 21 , wherein the one or more structural properties include, for each of one or more spatial dimensions in which the multiple panels are arranged, a number of panels into which the antenna array is structured in that spatial dimension. 
     
     
       23. The method of  claim 21 , wherein the one or more structural properties include a spatial arrangement of the multiple panels into which the antenna array is structured. 
     
     
       24. The method of  claim 21 , further comprising:
 determining a precoder based on the precoder recommended to the transmit radio node; and 
 precoding a transmission from the multi-panel antenna array using the determined precoder. 
 
     
     
       25. The method of  claim 24 :
 wherein the precoder is determined from an inter-panel precoding codebook; 
 further comprising receiving, from the wireless communication device, signaling indicating:
 an index indicating a recommended intra-panel precoder selected from an intra-panel precoding codebook; and/or 
 an index indicating a recommended polarization co-phasing precoder selected from a polarization co phasing precoding codebook. 
 
 
     
     
       26. The method of  claim 24 , wherein the determined precoder co-phases panels of the multi-panel antenna array. 
     
     
       27. The method of  claim 24 , wherein the determined precoder applies a phase offset between antenna ports corresponding to different panels that differs from a phase offset applied to antenna ports corresponding to the same panel. 
     
     
       28. The method of  claim 21  wherein the one or more structural properties include a total number of the multiple panels into which the antenna array is structured. 
     
     
       29. A wireless communication device configured for use in a wireless communication system, the wireless communication device comprising:
 processing circuitry; 
 memory containing instructions executable by the processing circuitry whereby the wireless communication device is configured to:
 determine, based on one or more structural properties of a multi-panel antenna array describing how the antenna array is structured into multiple panels, a precoder to recommend to a transmit radio node for applying to a transmission from the multi-panel antenna array; and 
 signal the determined precoder to the transmit radio node; 
 wherein the determined precoder is configured to apply, for each of the multiple panels, a panel-specific complex weight to all antenna ports corresponding to that antenna panel; and 
 wherein the panel-specific complex weight is a phase shift with unitary amplitude. 
 
 
     
     
       30. A transmit radio node configured for use in transmitting via a multi-panel antenna array in a wireless communication system, the transmit radio node comprising:
 processing circuitry; 
 memory containing instructions executable by the processing circuitry whereby the transmit radio node is configured to:
 transmit, to a wireless communication device, signaling indicating one or more structural properties of a multi-panel antenna array describing how the antenna array is structured into multiple panels 
 receive, responsive to the transmitting the signaling and from the wireless communication device, signaling indicating a precoder that the wireless communication device recommends to the transmit radio node for applying to a transmission from the multi-panel antenna array; 
 wherein the determined precoder is configured to apply, for each of the multiple panels, a panel-specific complex weight to all antenna ports corresponding to that antenna panel; and 
 wherein the panel-specific complex weight is a phase shift with unitary amplitude.